Neurology -- Correspondence for Kaida et al., 62 (5) 821-824

Correspondence published:

Reply to Haifeng: Susumu Kusunoki, Ken-ichi Kaida, Hiroshi Ashida (19 June 2004)

Anti-GQ1b antibody as a factor predictive of mechanical ventilation in Guillain-Barré syndrome: Li Haifeng (19 June 2004)

Reply to Haifeng 19 June 2004

Susumu Kusunoki,
Department of Neurology, Kinki University School of Medicine
377-2 Ohno-Higashi, Osaka-Sayama, Osaka 589-8511, Japan,
Ken-ichi Kaida, Hiroshi Ashida
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Re: Reply to Haifeng

kusunoki-tky{at}umin.ac.jp Susumu Kusunoki, et al.

We thank Dr. Haifeng for the comments on our article.[1] They question whether or not ophthalmoplegia and bulbar palsy are independent predictors. Our analyses on cranial nerve involvement, using a multiple logistic regression model, showed that neither ophthalmoplegia (p=0.07) nor bulbar palsy (p=0.23) was an independent variable, but facial diplegia was an independent variable (p=0.001). We would like to add the results as a postscript.
As they pointed out, most of the IgG anti-GQ1b antibodies also bind to GT1a and vice versa. [7] Clinical significance of the IgG activities against the respective antigens, GQ1b and GT1a, is therefore not easy to analyze. Actually, frequency of IgG anti-GT1a antibody, as well as that of IgG anti-GQ1b antibody, was significantly higher in GBS-AV(+) group than in GBS-AV(-) group. However, analyses using a multiple logistic regression model indicated that only IgG anti-GQ1b antibody is an independent predictor for artificial ventilation, being a definite result.
On the other hand, our results do not necessarily deny the possible association between IgG anti-GT1a antibody and respiratory failure. The association between the need for mechanical ventilation and the respective antibodies should be further investigated using the serum samples from a larger number of patients with GBS with IgG antibodies monospecific to either GQ1b or GT1a. In the meantime, basic research on the role of each antibody in the pathogenetic mechanisms of neurological diseases should be performed. Before that, it is practical to use the IgG anti-GQ1b antibodies, most of which cross-react with GT1a, as a marker predictive of the mechanical ventilation in GBS.
References
7) Chiba A, Kusunoki S, Obata H, et al. Serum anti-GQ1b IgG antibody is associated with ophthalmoplegia in Milller Fisher syndrome and Guillain- Barre syndrome: Clinical and immunohistochemical studies. Neurology 1993; 43: 1911-1917.

Anti-GQ1b antibody as a factor predictive of mechanical ventilation in Guillain-Barré syndrome 19 June 2004

Li Haifeng,
Department of Neurology, Affiliated Hospital of Medical College, Qingdao University
No. 16 Jiangsu Road, Qingdao, Shandong Province, P.R.China
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Re: Anti-GQ1b antibody as a factor predictive of mechanical ventilation in Guillain-Barré syndrome

drlhf{at}public.qd.sd.cn Li Haifeng

I read with interest the article by Kaida et al. [1] on the role of anti-GQ1b antibody as predicting mechanical ventilation in Guillain-Barre syndrome. We have known that bulbar dysfunction [2] and neck weakness [3] are independent predictors of mechanical ventilation. Laboratory markers of predictive value were lacking until Kaida’s challenging first step. We may anticipate that the anti-GT1a antibody is related to bulbar palsy. In their research, Kaida et al show that anti-GQ1b antibody is an independent predictor with a multiple logistic regression model. They found more patients have ophthalmoplegia or bulbar palsy in the ventilation group, but did not mention whether ophthalmoplegia is an independent predictor.
The anti-GQ1b antibody is associated with ophthalmoplegia, while anti-GT1a antibody is associated with bulbar palsy. Although in the ex vivo mouse diagram, anti-GQ1b-positive MFS serum induces a temporary dramatic increase of spontaneous quantal acetylcholine release and then makes transmission blockade at NMJ [4], there is no evidence that anti-GQ1b antibodies can cause respiratory failure in MFS or GBS. No similar effects of anti-GT1a antibodies were found until recently. Anti-GQ1b IgG antibodies were absorbed by GT1a in 98% of the tested sera [5], while anti-GT1a IgG cross reacted with GQ1b in 75% of the tested sera. [6] It is well known that patients with anti-GT1a IgG present with a variety of clinical conditions. A major part of this clinical variation was due to the coexistence of anti-GQ1b IgG. Anti-GT1a-positive patients frequently had ophthalmoplegia, bulbar palsy, ataxia, and areflexia. These features were also seen in patients with anti-GQ1b IgG.
There was no significant difference between the two groups with respect to the frequency of clinical findings. Whereas the subgroup who had anti-GT1a IgG without GQ1b reactivity frequently had preceding diarrhea as well as oropharyngeal, neck, and limb weakness. The distinctive clinical features and antibody profile indicate a specific subgroup within GBS. [6]
Because of the cross-reactivity of the two anti-ganglioside antibodies, they should not be used as independent variables in logistic regression model. If there is no evidence that anti-GQ1b and GT1a antibodies are associated with respiratory failure in GBS, we would like to see the link between clinical and laboratory data in before making conclusions, especially the overlapping of ophthalmoplegia and bulbar palsy and the cross-reactivity between anti-GQ1b and GT1a antibodies.
References
1. Kaida K, Kusunoki S, Kanzaki M, Kamakura K, Motoyoshi K, Kanazawa I. Anti-GQ1b antibody as a factor predictive of mechanical ventilation in Guillain-Barré syndrome Neurology 2004; 62: 821-824
2. Lawn ND, Fletcher DD, Henderson RD, et al. Anticipating mechanical ventilation in Guillain-Barre syndrome. Arch Neurol 2001; 58: 893-898.
3. Sharshar T, Chevret S, Bourdain F, et al. Early predictors of mechanical ventilation in Guillain-Barre syndrome. Crit Care Med 2003; 31: 278-283.
4. Jacobs BC, Bullens RW, O'Hanlon GM, et al. Detection and prevalence of alpha-latrotoxin-like effects of serum from patients with Guillain-Barre syndrome. Muscle Nerve 2002; 25: 549-558.
5. Susuki K, Yuki N, Hirata K. Fine specificity of anti-GQ1b IgG and clinical features. J Neurol Sci 2001; 185: 5-9.
6. Koga M, Yoshino H, Morimatsu M, et al. Anti-GT1a IgG in Guillain-Barre syndrome. J Neurol Neurosurg Psychiatry 2002; 72: 767-771.